I'm interested in your answers/thoughts/rationale. My thoughts for this one.
Water vapor condenses on a cold mirror.
dG = dH - TdS
You know dH for H2O(l) --> H2O(g) is + because heat must be added; therefore, dH must be - for the reverse.
S for gas is greater than S for a liquid because the liquid is more ordered. So dS from gas to liquid must be -.
So for dG = dH - TdS, in which dH is + and - TdS is -T(-S) +, then dG must be - so ---
Thermodynamic Signs
Determine the signs of ∆G, ∆H, and ∆S for the following three processes (for example, -+-,++-,+-+).
Water vapor condenses on a cold mirror.
Ethanol burns in air to form carbon dioxide and water vapor.
Dry ice sublimes at room temperature.
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